全文获取类型
收费全文 | 544篇 |
免费 | 19篇 |
专业分类
林业 | 13篇 |
农学 | 15篇 |
基础科学 | 5篇 |
79篇 | |
综合类 | 131篇 |
农作物 | 29篇 |
水产渔业 | 21篇 |
畜牧兽医 | 244篇 |
园艺 | 5篇 |
植物保护 | 21篇 |
出版年
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2014年 | 12篇 |
2013年 | 11篇 |
2012年 | 35篇 |
2011年 | 28篇 |
2010年 | 18篇 |
2009年 | 14篇 |
2008年 | 19篇 |
2007年 | 28篇 |
2006年 | 18篇 |
2005年 | 26篇 |
2004年 | 18篇 |
2003年 | 16篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 13篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1971年 | 5篇 |
1970年 | 9篇 |
1969年 | 7篇 |
1968年 | 6篇 |
1967年 | 5篇 |
1924年 | 8篇 |
排序方式: 共有563条查询结果,搜索用时 46 毫秒
81.
Singh BN Hayes GR Lucas JJ Beach DH Gilbert RO 《American journal of veterinary research》2005,66(7):1181-1186
OBJECTIVE: To evaluate the cytopathic effects of Tritrichomonas foetus and a purified cysteine protease (ie, CP30) of T foetus on cultured bovine uterine epithelial cells (BUECs) in vitro. SAMPLE POPULATION: 10 reproductive tracts were obtained from late-term bovine fetuses at a commercial abattoir. PROCEDURE: An in vitro culture system of BUECs was developed to study the cytopathic effects of T foetus and purified CP30 of T foetus on host cells. Cytotoxicity of T foetus or CP30 on exposed BUECs was determined. Fluorescence microscopy and flow cytometry analyses were used to detect apoptosis. A fluorometric assay was used to detect BUEC caspase 3 activation. The CP inhibitor E-64 and a caspase inhibitor were used to inhibit apoptosis. RESULTS: Cytopathic effects were observed in BUECs treated with parasites or CP30 and were concentration and time dependent. The BUECs underwent apoptosis in the presence of parasites or CP30. The specific CP inhibitor E-64 abolished the induction of apoptosis in BUECs by CP30. The caspase inhibitor reduced the amount of apoptosis in BUECs. CONCLUSIONS AND CLINICAL RELEVANCE: T foetus and its CP30 induce apoptosis in cultured BUECs in vitro. Induction of apoptosis by CP30 is correlated with protease activity. Endometrial cell death as a result of a T foetus infection is likely to be more important in mediating infertility than a direct effect on the conceptus. Provoking an apoptotic reaction in the host may mitigate an inflammatory reaction or immune response and therefore favor survival of the parasite in a chronic infection. 相似文献
82.
83.
Isolation of bovine viral diarrhoea viruses from bison 总被引:2,自引:0,他引:2
Deregt D Tessaro SV Baxi MK Berezowski J Ellis JA Wu JT Gilbert SA 《The Veterinary record》2005,157(15):448-450
84.
Kelly AM Kahn GS 《Journal of the American Veterinary Medical Association》2005,226(11):1798; author reply 1798
85.
Observations on the laying behaviour of hens in battery cages 总被引:1,自引:0,他引:1
Observations were made on the laying behaviour of hens from each of two commercial strains kept in a Thornber battery cage system. Attention was paid to the following behavioural components of oviposition: the position of the hen in the cage; the stance of the hen; the height through which the egg fell; the orientation of the egg; the time taken to oviposit; the time taken for the egg to roll out of the cage and the incidence of pecking at the egg.
Less detailed observations were made on the pre‐laying behaviour of the hens. 相似文献
86.
87.
R P Gilbert C T Gaskins J K Hillers J S Brinks A H Denham 《Journal of animal science》1988,66(10):2490-2497
Immunoglobulin G1 concentration (IgG1) was measured in presuckle colostrum and calf serum obtained at 36 h and at weaning from inbred and straightbred Angus, Brangus, Hereford, Red Angus and Simmental cattle. Sources of variation considered as dam traits examined for IgG1 in colostrum and 36-h calf serum included line of sire, sire within line, age, and linear regression of IgG1 on inbreeding of dam. Only line of sire and inbreeding of dam were significant in the analysis of 36-h calf serum. Sources of variation considered as calf traits examined for IgG1 in calf serum at 36 h and at weaning included line of sire, sire within line, sex of calf, age of dam, and regressions of calf serum IgG1 on inbreeding of the calf and on dam's colostral IgG1. Only sire within line and the regression on dam's colostral IgG1 were significant for calf serum IgG1 at 36 h. Large differences existed in 36-h calf serum IgG1 between sires both within lines and when lines were ignored. Calves with 36-h serum IgG1 of less than 10 mg/ml were two to four times more likely to die before weaning than calves with higher IgG1 levels. The heritability estimates of IgG1 by paternal half-sib analysis were .41 +/- .30 for colostrum measured as a trait of the dam and .56 +/- .25 for 36-h. calf serum and .05 +/- .17 for calf serum at weaning considered as a trait of the calf. These estimates indicate that IgG1 in colostrum and 36-h calf serum could be increased by selection.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
88.
An enzyme-linked immunosorbent assay was developed for detecting antibody to coccidia to facilitate the survey of laboratory and field infections. Serum antibody levels in chickens were measured against soluble Eimeria tenella oocyst antigen. Sera from breeders aged 10, 23, 37, and 43 weeks were positive with uniformly high antibody titers. Broiler chick sera showed high maternal antibody titer at hatch, decreasing to an almost negligible response at 3 weeks of age. Two-week-old broiler chicks had variable responses to a single infection of E. tenella: titers were elevated at 8 to 10 days postinfection and generally increased through day 24. Weekly reinfection of 2-week-old broiler chickens produced an antibody titer in proportion to the number of oocysts per dose and stimulated protection against challenge with 2 x 10(5) E. tenella. Inbred birds raised in a pathogen-free environment for 6 weeks had no detectable antibody titers. 相似文献
89.
Marion D. Francis Candice L. Slough Hugh E. Black Andrew J. Tofe G. Gilbert Cloyd 《Veterinary radiology & ultrasound》1980,21(4):168-176
The following sequence of treatments was administered to a Saint Bernard dog with a primary distal right radius osteosarcoma: 54 days of daily disodium 1-hydroxyethylidenediphosphonate (HEDP) subcutaneous injections; 53 days of HEDP per os ; one 32 P-HEDP intravenous injection. During the pretreatment period, there was an extensive increase in calcific tumor growth and osteoblastic proliferation. After the subcutaneous HEDP treatment, almost complete tumor necrosis was seen. After the oral HEDP treatment, only the deepest tumor portion contained active osteoblasts, calcific growth of the tumor was completely blocked, and uptake of 99m Tc-Sn-HEDP was reduced to one fourth of the pretreatment uptake. After a single 32 P-HEDP dose, large areas of tumor necrosis were evident histopathologically. However, subsequent resumption of cellular activity occurred in the tumor, and the uptake of 99m Tc-Sn-HEDP increased to pretreatment values. These data suggest that systemically administered HEDP should be studied further for its possible therapeutic potential in the treatment of osteosarcoma and indicate a need for further study of 32 P-HEDP or possibly 33 P-HEDP. 相似文献
90.
OBJECTIVE: To determine the pharmacokinetics of doxorubicin in sulphur-crested cockatoos, so that its use in clinical studies in birds can be considered. DESIGN: A pharmacokinetic study of doxorubicin, following a single intravenous (i.v.) infusion over 20 min, was performed in four healthy sulphur-crested cockatoos (Cacatua galerita). PROCEDURE: Birds were anaesthetised and both jugular veins were cannulated, one for doxorubicin infusion and the other for blood collection. Doxorubicin hydrochloride (2 mg/kg) in normal saline was infused i.v. over 20 min at a constant rate. Serial blood samples were collected for 96 h after initiation of the infusion. Plasma doxorubicin concentrations were assayed using an HPLC method involving ethyl acetate extraction, reverse-phase chromatography and fluorescence detection. The limit of quantification was 20 ng/mL. Established non-parametric methods were used for the analysis of plasma doxorubicin data. RESULTS: During the infusion the mean +/- SD for the Cmax of doxorubicin was 4037 +/- 2577 ng/mL. Plasma concentrations declined biexponentially immediately after the infusion was ceased. There was considerable intersubject variability in all pharmacokinetic variables. The terminal (beta-phase) half-life was 41.4 +/- 18.5 min, the systemic clearance (CI) was 45.7 +/- 18.0 mL/min/kg, the mean residence time (MRT) was 4.8 +/- 1.4 min, and the volume of distribution at steady state (V(SS)) was 238 +/- 131 mL/kg. The extrapolated area under the curve (AUC(0-infinity)) was 950 +/- 677 ng/mL x h. The reduced metabolite, doxorubicinol, was detected in the plasma of all four parrots but could be quantified in only one bird with the profile suggesting formation rate-limited pharmacokinetics of doxorubicinol. CONCLUSIONS AND CLINICAL RELEVANCE: Doxorubicin infusion in sulphur-crested cockatoos produced mild, transient inappetence. The volume of distribution per kilogram and terminal half-life were considerably smaller, but the clearance per kilogram was similar to or larger than reported in the dog, rat and humans. Traces of doxorubicinol, a metabolite of doxorubicin, were detected in the plasma. 相似文献